Transfer switch



R. L. BARRY TRANSFER SWITCH May 1, 1934.

Filed Aug. 20, 1952 2 Sheets-Sheet l R. L. BARRY TRANSFER SWITCH May 1, 1934.

Patented May 1, 1934 UNITED STATES PATENFy OFFICE TRANSFE R SWITCH Application August 20,

4 Claims.

This invention relates to improvements in transfer switches particularly adapted for use in connection with mine locomotives of the gathering type for transferring electric power to the 5 locomotive through one power inlet or another.

This invention has among other objects to provide a new and improved interlocked transfer switch for controlling the connection of the locomotive circuit with a source of current supply through one of a plurality of power inlets, such as a trolley or one of a plurality of trolleys or a cable reel, which transfer switch may automatically transfer from one of the power inlets to the other and is so arranged as to prevent the locomotive from obtaining current from any one of the power inlets while any other of the power inlets is in use.

My invention may be more clearly understood with reference to the accompanying drawings wherein:

Figure 1 is a schematic view of a mine locomotive showing the wiring connections thereto;

Figure 2 is an enlarged side elevation of the transfer switch of my invention with parts broken away and in section to more clearly show the details thereof;

Figure 3 is a plan View of the transfer switch embodying my invention with parts broken away and in section to more clearly show the details thereof; and

Figure 4 is an enlarged detail Side elevation of a portion of the transfer switch shown in Figure 2 with different parts broken away than are shown in Figure 2.

Like numerals refer to like parts throughout the various iigures.

Referring now in particular to the details of the drawings, the device embodying my invention comprises a locomotive of the gathering type adapted to receive power from a source of power supply through suitable current conducting means, such as a trolley line through one or another of a plurality of power inlets which are herein preferably shown as comprising trolleys `12 and 13 and a cable reel 14.

Gathering locomotives of the type herein shown are usually provided with either a single motor or a pair of motors connected in series or parallel for propelling the locomotive about the mineA The propulsion means for the locomotive herein schematically shown in Figure l comprises two motors l5 connected together in series. The motors 15 are adapted to receive electric power through either of the trolleys 12 or 13 or the jcable reel 14, a transfer switch generally indicated 1932, Serial No. 629,613

by reference character 16, and an electric controller generally indicated by reference character 17 in a usual manner well known to those familiar with the art.

Referring now in particular tothe details of the transfer switch 16 and several of the novel features of my invention, said transfer switch includes a casing 18 preferably constructed in a manner to prevent arcing therein from igniting the mine gases outside of said casing. The casing 18 has suitable electric circuit closing means supported therein in a usual manner for connecting the locomotive motors 15 to the source of power supply through either of the trolleys 12 or 13 or the cable reel 14. The circuit closing 70 means may be of any type well known to those skilled in the art and are herein preferably shown as comprising electric contactors of a usual construction and include a separate contactor for each power inlet.

The circuit closing means for connecting the locomotive motors 15 to the cable reel 14 comprises a contractor 19 which connects the motors 15 with the cable reel 14 by means of a conductor 20 leading from the cable reel 14 to a stationary s@ contact 21, and a conductor 22 leading from a movable contact 23 to the controller 17 and said locomotive motors.

The circuit closing means for connecting the locomotive motors 15 to the trolley 12 comprises 85 a contactor 25 which connects the motors 15 with the source of power supply through the trolley 12 by means of a stationary contact 26 connected with said trolley through a conductor 27 and a movable contact 28, having connection with the controller 17 and said locomotive motors through the conductor 22.

Likewise, another contactor 29 is provided to connect the motors 15with the source of power supply-through the trolley 13 by means of a stationary contact 30 having connection with the trolley 13 by means of a conductor 31 and a movable contact 32 having connection with the controller 17 and motors 15 by means of the conductor 22.

The contactors 19, 25, and 29 are of a similar construction and include the aforementioned stationary and movable contacts engageable with each other to close the circuit from either of the trolleys 12 or 13 or the cable reel 14 to the locomo- 105 tive. The movable contacts 23, 28, and 32 are mounted on the upper end of rocking arms 33,

34, and 35, respectively. Suitable electro magnets 36, 37, and 38 are provided to attract the rocking arms 33, 34, and'35, respectively, and engage each 110 CII respective movable contact thereon with its respective stationary contact. The rocking arms 33, and 35, and the respective movable contacts 28, 28, and 32, are of surlicient weight to be disengaged from the respective stationary contacts 21, 26, and 30 by gravity when current is cut on or the respective magnets 35, 37, and 38.

Electric current energizes the electro magnet by means or a conductor 39 connected from the conductor 2o to the positive side of the coil for said magnet and a conductor connected from the negative side of the coil for said magnet to ground through a suitable push button switch indicated at 41. In a similar manner the electro magnet 37 is energized by a conductor 42 connected from the conductor 2'.7 to the positive side oi the coil for said magnet and a connection from the negative side of the coil for said magnet to the conductor 4G. The electro magnet 38 is likewise energized by means or" a conductor 43 connected from the conductor 31 to the positive side of the coil for said magnet and a connection from the negative side of the coil for said magnet to the conductor 40. t may thus be seen that when the push button switch 41 is in a closed position and either of the trolleys 12 or 13 or the cable reel 14 is connected to the source of current supply, that either the electro magnet 36, 37, or 38 is energized depending upon which power inlet is connected to the source of power supply which electro magnet will close the respective contacter associated therewith.

Referring now in particular to the means for preventing the closing of any one contacter when any other contacter is in a closed position and one of the novel features of my invention, a new and improved interlocking mechanism generally indicated by reference character 44 is provided. The interlocking mechanism 44 comprises a multi-throw crank 45 journaled at its ends in the casing 18 for the transfer switch 16 and insulated therefrom in a suitable manner and having each of its crank arms connected to the contactors 19, 25, and 29 in a manner which will hereinafter be more fully described.

A connecting member 47 is provided to connect a crank arm 48 of the multi-throw crank 45 with the rocking arm 33 of the contacter 19. The connecting member 47 is fabricated from a number of pieces and has a clevised end adapted to have pivotal connection with the rocking arm 33 in a usual manner, and an opposite end detachably secured thereto made from a suitable insulating material having an elongated slot 49 therein, which elongated slet is adapted to have slidable connection with the crank arm 48. The end of the connecting member, having connection with the crank arm 48, is split so it may readily be engaged with or disengaged from said crank arm in a usual manner clearly illustrated in Figures 2 and 4. The elongated slot 49 is so arranged as to permit opening of the contacter 19 at any time but prevent closing of said contacter except when the crank arm 48 is in the proper position and to hold the multi-throw cra-nk 45 from rotation when the contacter 19 is in a closed position.

In a similar manner, a connecting member 50 constructed in the same manner as the connectx ing member 47 connects the rocking arm 34 of the contacter 25 with a crank arm 51 of the multi-throw crank 45. The connecting member 50 is similarly provided with an elongated slot 52 which is journaled on the crank arm 51. The portion of the connecting member 50, having the elongated slot 52 therein, is made from a suitable insulating material so as to insulate the rocking arm 34 from the multi-throw crank 45.

The elongated slot 52 is similarly arranged so as to permit opening of the contacter 25 but to prevent closing of said contacter except when the crank arm 51 is in the proper position and to hold the multi-throw crank 45 from rotation when said contacter is in a closed position.

Likewise, a connecting member 53 is provided to connect the rocking arm 35 of the contacter 29 with a crank arm 54 ci' the multi-throw crank 45. The connecting member 53 is constructed in the same manner as the connecting member 47 and the connection from the connecting member 53 to the crank arm 54 includes a portion made from a suitable insulating material having an elongated slot 55 formed therein permitting opening of the contacter 29, but preventing closing of said contacter except when the crank arm 51 is in the proper position, and holding the multi-throw crank 45 from rotation when said contacter is in a closed position.

The crank arms 48, 5l, and 54 are located equidistantly from the center of rotation of the multithrow crank 45 and are coincident with radial lines extending from the center of said multithrow crank spaced equidistantly apart, herein shown as being spaced 120 apart, so that when one contacter is in a closed position the other contactors will be locked in an open position by their respective connecting member and the multi-throw crank 45.

It is apparent that where more or less power inlets are provided with the resultant increase or decrease in the number of contactors used, that the spacing of the crank arms on the interlocking mechanism will vary, but that said crank arms will still be coincident with radial lines spaced equidistantly apart, the spacing being dependent on the number of ccntactors interlocked. It may thus be seen that the interlocking mechanism shown herein is expansible to interlock an unlimited number of contactors when desired.

Thus, when the contactors 19, 25, and 29 are in an open position and the circuit through the magnets 36, 37, and 88 is closed by the push button switch 41, and either of the trolleys 12 or 13 or the cable reel 14 is connected with the source of power supply, the contacter associated therewith will be closed and closing of said contacter will rotate the multi-throw crank 45 through the respective connecting rod connected between said contacter and a crank arm of the multi-throw crank 45, which multi-throw crank will hold the other two contacts in an open or disengaged position. When current is disconnected from the closed contacter, the slot formed in the connecting member connecting this member with the multi-throw crank 45 permits this contacter to open.

It may thus be seen that applicant has provided a new and improved transfer switch of a simplified construction for mine locomotives of the gathering type controlling the application of electric power to the locomotive through one of a plurality of power inlets which automatically connects the locomotive motors to the source of power supply as soon as one of said power inlets is connected to said source of power supply providing the push button switch 41 is in a closed position. It may also be seen that this transfer switch is so arranged as to automatically disconnect the motors from the source of power supply as soon as either one of the power inlets is disconnected from said source of power supply and that applicants transfer switch is so arranged that one power inlet may only be connected to the source of power supply at a time, the other power inlets being positively locked in an open position by means of the interlocking mechanism 44, thus preventing arcing or burning of the locomotive parts and injury to the locomotive operator or men coming in contact with the locomotive. It should be further noted that this interlocking mechanism is of a simplified and novel construction so arranged as to be confined in small areas and prevent a drag on the respective contactors as they1 are being closed which may readily be expanded to interlock as many contactors as desired by increasing the crank arms on the multi-throw crank 45.

Although I have herein shown and described one form in which my invention may be embodied, it will be understood that the construction and arrangement of the various parts may be changed or altered without departing from the spirit and scope thereof. Moreover, I do not wish to be construed as limiting myself to the particular form illustrated, excepting as it may be specifically limited in the appended claims.

I claim as my invention:

l. A transfer switch having a plurality of current inlets, a contact connected with each of said current inlets, a plurality of movable conn tacts, each of said movable contacts being mounted on a pivotally movable arm for engagement with one of said first mentioned contacts, a magnetic coil associated with each of said movable contacts and connected in series with each of said current inlets for pivotally moving said pivotally movable arms and engaging said movable contacts with said first mentioned contacts when current inlets are connected with a source of power supply, and interlocking means for preventing more than one of said movable contacts from engaging said first mentioned contacts when current is applied to more than one of said current inlets comprising a multi-throw crank member and a slidable connection between each throw of said crank member and one of said movable contacts.

2. A transfer switch having a plurality of current inlets, a contact connected with each of said current inlets, a plurality of movable contacts, each of said movable contacts being mounted on a pivotally movable arm for engagement with one of said first mentioned contacts, a magnetic coil associated with each of said movable contacts and connected in series with each of said current inlets for pivotally moving said pivotally movable arms and engaging said movable contacts with said first mentioned contacts when said current inlets are connected with a source of power supply, and interlocking means for preventing more than one of said movable contacts from engaging said first mentioned contacts when current is applied to more than one of said current inlets comprising a multi-throw crank member, each throw being coincident with radial lines spaced an equal distance apart, and a plurality of connecting members, each connecting member slidably connecting each throw of said crank member with one of said movable contacts.

3. A transfer switch having a plurality of current inlets, a contact connected with each of said current inlets, a plurality of movable contacts, each of said movable contacts being mounted on a pivotally movable arm for engagement with one of said first mentioned contacts, a magnetic coil associated with each of said movable contacts and connected in series with each of said current inlets for pivotally moving its associated pivotally movable arm and engaging said movable contact with said first mentioned contact when said respective current inlet is connected with a source of power supply, and interlocking means for preventing more than one of said movable contacts from engaging said first mentioned contacts when current is applied to more than one of said current inlets comprising a multi-throw crank member, each throw being coincident with radial lines spaced an equal distance apart, and means for connecting each throw of said crank member with one of said movable contacts comprising a plurality of connecting members having pivotal connection with said movable contacts and slidable connection with each throw of said multi-throw crank member.

4. A transfer switch having a plurality of current inlets, a contact connected with each of said current inlets, a plurality of movable contacts, each of said movable contacts being mounted on a pivotally movable arm for engagement with each of said first mentioned contacts, a magnetic coil associated with each of said movable contacts and connected in series with each of said current inlets for pivotally moving said pivotally movable arms and engaging said movable contacts with said first mentioned contacts when said current inlets are connected with a source of power supply, and interlocking means for preventing more than one of said movable contacts from engaging said rst mentioned contacts when current is applied to more than one of said current inlets comprising a multi-throw crank member, each throw being coincident with radial lines spaced an equal distance apart, and means for connecting each throw of said crank member with one of said movable contacts whereby any one of said movable contacts may be disengaged from its respective stationary contact but none of said movable contacts may be engaged with their respective stationary contact while any other movable contact is engaged with a sta.- tionary contact comprising a plurality of connecting members, each of said connecting members having pivotal connection with one of said pivotally movable arms and slidable connection with one throw of said multi-throw crank member.

ROBERT L. BARRY. 

